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Gravel on base of tank?
http://byap.backyardmagazines.com/forum/viewtopic.php?f=1&t=581		 Page 1 of 2
Author:  Marcus [ Sep 24th, '06, 07:20 ]
Post subject:  Gravel on base of tank?
If aquariums have gravel on the tank base to aid in beneficial bacteria growth (generally with an under gravel filter) and cleaned with the use of a ‘gravel vacuum’ is there merit in having gravel on the base of an Aquaponics tank (whether practical or beneficial)?

I welcome debate on this topic!
Author:  Aquaddict [ Sep 24th, '06, 07:39 ]
Post subject:  Re: Gravel on base of tank?
It all depends on the situation/size of the system.

I like UGF's in hobby sized systems. The gravel removes solids before water goes to your plants so it makes perfect sense to use them. Especially if growing a hobby sized floating culture. With a bed you will have plenty of gravel filter anyway (hopefully).

I never had to vacuum with an aquaponic UGF, it was always clean once things got cycled.

I have a wee tank just came free I will try just that - a ugf going to deep water culture.

You may have just helped solve a design problem for me in trying to simplify Aqua nft :D
Author:  GotFish? [ Sep 24th, '06, 08:48 ]
Post subject: 
AA, I thought one of the problems with a UGF is it gets clogged easily. Is it a bad thing to never clean the bottom of an aquarium? In terms of the fish poo remaining and not being broken down?
Author:  aquamad [ Sep 24th, '06, 09:26 ]
Post subject: 
In my large 1000L tank I NEVER cleaned the gravel - never neede to! The plants and bacteria took care of it all for me
Author:  steve [ Sep 24th, '06, 09:37 ]
Post subject: 
With out a doubt i think UGF's are one of the most efficient and simple methods of a crystal clear aquarium, but i've never used one in my aquariums becasue they are a Pain in the ass to clean. Substrate in your AP system is not going to be an UGF unless you have some type of airlift grid under it. Personally i think having the solids removal as part of the growbeds is the go.

HOWEVER

IF you're thinking of having simly a substrate in your AP fish tank then i don't think its necessarily a bad idea. These are uncharted waters. I believe julie is contemplating putting a sand substrate in her AP pool conversion.

Id say a finer substrate like sand would be better, as solids would tend to stay above the and on the sand, being able to be kept in suspension and taken up by the pump to the growbeds. The coarser your substrate the more of the solids are going to fnd their way into the cracks and grooves and become anerobicly decomposed.

Marcus, you've just put your hand up as a test subject :)
Author:  aquamad [ Sep 24th, '06, 09:45 ]
Post subject: 
Quote:
sad substrate

lol
Author:  steve [ Sep 24th, '06, 09:58 ]
Post subject: 
You're reading these posts far too slowly Mr Mad.

Thanks :) i'm sure it will be a very HAPPY substrate :)
Author:  monya [ Sep 24th, '06, 13:47 ]
Post subject: 
I cleanedmy goldie gravel for the first timein ages yesterday. Virtually no sludge, can only put it down to a healthy system. One sad note though, I gave the cartridge fiter a cleanout, put it back together the wrong way, and 2 goldie got sucked into the plastic core. Only found them becasue the filter didn't seem to be pushing out much water. These are my first 2 deaths since I started my mini system in May.
Author:  bundaberg kid [ Sep 24th, '06, 14:13 ]
Post subject: 
The substrate flooring might look purdy but isnt the grow bed the filter? a UGF in this situation would take out all the good stuff (lol was gunna say "good shit" but decided to keep it clean) and depfeat the purpose of the whole balancd system thing.

Unless there was a way to draw the solids from the UGF...but what a pain in the arse that would be.


Hey steve has the weather been just as cvrap up there as it has in Cranbourne today........I almost ended up in Oz with Toto
Author:  nick [ Sep 24th, '06, 16:25 ]
Post subject: 
isn't the best way to use an UGF is to actually take water from the top and put it under the filter bed so that water moves up and away and not down and into the bed. THis requires a power head but you get the bonus of having freshly oxygenated water in the filter.
Author:  Aquaddict [ Sep 24th, '06, 16:36 ]
Post subject: 
Anything can be the filter. Plants roots, broken pots, UGF's, growbeds... The solids will be broken down by bacteria (filter) and utilised by the plants if the system recirculates and is designed properly.

There's ratios to figure out but a well made ugf could make for a very sweet set-up with what I have in mind.

Steve, do you know what the maximum allowable depth of a ugf is? With what I want the deeper the better within reason. And tell me about airlifts if you don't mind...

I want to pull water down through a deep UGF set on the bottom of the tank with (hopefully) 25 cm's of medium filter above. This would be small medium (5mm) at the base going to larger (25mm) on top.

I need to keep this completely aerobic and so plan to have heavily aerated water drawn down through it (and pumped out) at a rate of approx 1000 lph per cubic metre of 'ugf'. Water depth would not exceed 700 mm above the ugf.

Aqua ugf's are clean, been there ;) But 25cm's??? Not been there...
Author:  bundaberg kid [ Sep 24th, '06, 17:01 ]
Post subject: 
Sorry AD.was sufferin from tunnel vison lol, was taking a breather whilst tryn to finish me green house frame b4 the storm(that didnt turn up) turned up.

Was focussed on the traditonal filtering setup(growbeds) that most have been using . Would you still get the same amount of nutrients etc to the grow bed if the UGF has already broken down and maybe even digested the solids?
Author:  Aquaddict [ Sep 24th, '06, 18:24 ]
Post subject: 
Not exactly no. The bacteria themselves take some energy to survive. But it's not much. They will crash with no food so they do consume it. Luckily most of their 'waste' is what we want.
Author:  steve [ Sep 24th, '06, 21:10 ]
Post subject: 
AA, not sure on exact specs for UGF, and now nick has me thinking i might have the theory of operation wrong.

in any case, one of the main problems with both cannister and UGF's will be water "channeling".

Nick, can you do some research on UGFs for us?

Steve
Author:  nick [ Sep 25th, '06, 00:59 ]
Post subject: 
I did some prelim research and must have been thinking wrong with the powerhead attachment to the UGF. The powerhead replaces the air stone in moving the water around. The more powerul powerhead resists the blockages that can occur in undergravel filters. The airstone water lift system as I understand it is simple but poorly powered and when the UGF begins to block as it sometimes does it cnnot draw water through making the issue worse, the powerheads as I read it aid in this.

Steve I cannot remember at this time of morning where I read the bit about reverse flow using powerheads but will have a more thourough look in the later than now morning.

I think if we are aiming to have something with a large surface area to allow for bacterial growth than a pull through removable internal filter would be a good start. Some pumps can have pipes added at the draw in section which mean you could have something like a 20 litre drum with the top cut off filled with bioballs that sits in the tank and has the hose to the pump out of the bottom and thus it would suck water down and into the pump and then over the growbeds. I know this is confusing but will try to explain it better later.

Nick
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